1. Technical Field
This invention relates generally to communication systems and, more particularly, to Radio Frequency (RF) signal amplification within wireless devices operating in wireless communication systems.
2. Related Art
Communication systems are known to support wireless and wire-lined communications between wireless and/or wired communication devices. Such communication systems range from national and/or international cellular telephone systems to the Internet to point-to-point in-home wireless networks. Each type of communication system is constructed, and hence operates, in accordance with one or more communication standards. For instance, wireless communication systems may operate in accordance with one or more standards including, but not limited to, IEEE 802.11, Bluetooth, advanced mobile phone services (AMPS), digital AMPS, global system for mobile communications (GSM), code division multiple access (CDMA), wireless application protocol (WAP), local multi-point distribution systems (LMDS), multi-channel-multi-point distribution systems (MMDS), and/or variations thereof.
Depending on the type of wireless communication system, a wireless communication device, such as a cellular telephone, two-way radio, personal digital assistant (PDA), personal computer (PC), laptop computer, home entertainment equipment, etc., communicates directly or indirectly with other wireless communication devices. For direct communications (also known as point-to-point communications), the participating wireless communication devices tune their receivers and transmitters to the same channel of the other parties (e.g., one of a plurality of radio frequency (RF) carriers of the wireless communication system) and exchange information over that channel. For indirect wireless communications, each wireless communication device communicates directly with an associated base station (e.g., for cellular services) and/or an associated access point (e.g., for an in-home or in-building wireless network) via an assigned channel. To complete a communication connection between the wireless communication devices, the associated base stations and/or associated access points communicate with each other directly, via a system controller, via the public switched telephone network (PSTN), via the Internet, and/or via some other wire-lined or wireless network.
Each wireless communication device includes a built-in radio transceiver (i.e., receiver and transmitter) or is coupled to an associated radio transceiver (e.g., a station for in-home and/or in-building wireless communication networks, RF modem, etc.) to participate in wireless communications. As is known, the receiver receives RF signals, removes the RF carrier frequency from the RF signals via one or more intermediate frequency stages, and demodulates the signals in accordance with a particular wireless communication standard to recapture the transmitted data. The transmitter converts data into RF signals by modulating the data in accordance with the particular wireless communication standard and adds an RF carrier to the modulated data in one or more intermediate frequency stages to produce the RF signals.
As is also known, the receiver is coupled to an antenna and includes a low noise amplifier (LNA), zero or more intermediate frequency stages, a filtering stage, and a data recovery stage in many designs. The low noise amplifier receives an inbound RF signal via the antenna and amplifies it. Down converters mix the amplified RF signal with one or more local oscillations to convert the amplified RF signal into a baseband signal or an intermediate frequency (IF) signal. As used herein, the term “low IF” refers to both baseband and low intermediate frequency signals. A filtering stage filters the low IF signals to attenuate unwanted out of band signals to produce a filtered signal. The data recovery stage recovers raw data from the filtered signal in accordance with the particular wireless communication standard.
As the demand for enhanced performance (e.g., reduced interference and/or noise, improved quality of service, compliance with multiple standards, increased broadband applications, etc.), smaller sizes, lower power consumption, and reduced costs increases, wireless communication device engineers are faced with a very difficult design challenge to develop such a wireless communication device.
Bluetooth is a standard for providing a wireless solution to cables that are used to couple electrical devices to each other. Generally, Bluetooth may be used to replace cabling between computers, printers, and other computer peripheral devices, as well as peripheral devices for other systems, such as mobile phones, etc. Generally, a Bluetooth radio device up-converts data typically carried on a cable to an RF frequency for transmission to an RF receiver. Accordingly, Bluetooth is facilitating the use of RF-based keyboards, mice, headsets, etc. One advantage of Bluetooth is that its low power consumption gives long battery life for cordless devices that are generally portable. Significant aspects of Bluetooth include its robustness, low complexity, low power, and low cost. Moreover, Bluetooth systems are designed to operate in noise environments and are operable to perform frequency hopping to make a link robust. A Bluetooth device typically includes a radio that transmits and receives the RF frequency signals at a 2.4 GHz frequency band. A Bluetooth device may further include a baseband processor that performs low level link routines and executes baseband protocols. The baseband processor includes logic to establish a link, provide access to hardware for the Bluetooth device through a host controller interface and supports higher level protocol multiplexing, packet segmentation and reassembly, and the conveying of quality of service information.
Another protocol embedded in a Bluetooth device is a service discovery protocol (SDP) which provides a method for two Bluetooth devices to communicate and to discover what services may be provided by either or both of the Bluetooth devices. It further allows the devices to determine what characteristics of the available services exist. Service discovery protocol is a simple protocol that uses a request/response model wherein each transaction includes a request protocol data unit and a response protocol data unit. In some applications, the requests and responses may be pipelined. Every SDP packet data unit includes a packet data unit header followed by packet data unit specific parameters. The header, more specifically, includes three fields: a PDU ID field, which identifies the type of PDU (its meaning and the specific parameters, a transaction ID field that uniquely identifies request PDUs and is used to match response PDUs to request PDUs, and a parameter link field that specifies the link of all parameters contained in the PDU.
One key aspect of SDP is to allow Bluetooth devices to discover what services other Bluetooth devices can offer. Typically, a Bluetooth device will search for a specific service and, upon detecting another Bluetooth device, will browse to determine what services may be offered by the other Bluetooth device.
Current technology for authentication for access to a device, to an entry point, or to authenticate a transaction, has always required a user to input a user name or ID, a password, or a type of biometric input that allows validation. Such techniques have generally been considered reliable though they are at times cumbersome and can even result in long lines of people waiting to access an entry point or device. For example, in a workplace, lines to enter the facility at a designated time may be quite long because each person must enter his or her own user ID. While Bluetooth offers some relief to such a scenario, for example, so-called Bluetooth RF ID in which a single identify code is stored in the Bluetooth device, the access is limited only to the service provider that corresponds to the particular access ID. Thus, while an employee might use a badge with a Bluetooth RF ID to gain access to a particular doorway, the employee would then have to manually enter IDs or carry additional Bluetooth devices with RF IDs.
FIG. 1 is a functional block diagram of a prior art Bluetooth piconet comprising an RF ID system. As may be seen, a Bluetooth host 02 is operatively coupled to communicate with a Bluetooth service provider 04. In a system in which the Bluetooth service provider is a Bluetooth master, the Bluetooth host would seek a beacon produced by the master and would reply to the beacon to gain access over an RF frequency. As a part of establishing a link between the Bluetooth host 02 and the Bluetooth service provider 04, the Bluetooth host 02 provides a secure RF ID to the Bluetooth service provider 04. In a typical system, the ID is stored permanently in a permanent memory register coupled to a processor which then provides the ID to a Bluetooth radio transceiver that transmits the RF ID to the Bluetooth service provider 04 for authentication. Such a device is advantageous in that it removes a need for a user of the Bluetooth host 02 to manually enter a user name, password, or other type of ID, but is disadvantageous in that the user must have a Bluetooth host 02 for every device or point-of-entry to which the user seeks access without having to manually enter authentication information.
Generally, to avoid having to manually enter an ID, an individual would have to carry a Bluetooth device with an RF ID capability for each system or entry point to which he or she desires access. What is needed, therefore, is a system and method that provides seamless access to differing types of devices and entryways.